In Russia, the host must register an alien within a week of their arrival (assuming they stay more than a week). How do independent travellers not staying in hotels at all do? Do they need to register at all? For example, I might spend the first three Russian nights on the train and the rest trekking and camping in a national park. Other people might drive a campervan and use that a a place to sleep. I have read that If you make the Trans-Siberian route by train and sleep on it, in this case the train ticket would be equivalent to the registration (you always have to keep your ticket in handy). — does that mean the Russian railways register the alien? Can they also do it if I spend two nights on the train to some domestic destination, without going into any ordinary accommodation from there? Or can the "inviting company" (which uses a fake itinerary) perform this registration? How does this work? Wikivoyage claims that if you do not intend to stay at the hotels, you may, at your own risk, forego the registration procedure, but I'm a bit scared to take their word for it. What risk?
Having a long-distance rail or airplane ticket on a date is a proof that you have arrived on that date, so the "n days to register" counter is reset on that date.
I'm not aware that anyone was bothering travelers with registration requirements in the past 15 years, but here you go anyway. If you travel every few days you are virtually extempt from registration rules. Please note that Russian long-distance rail and plane tickets are bound to a specific person so they do in fact "register" your location.